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Thismia limkokthayi, a distinct mitriform species of the mycoheterotrophic genus Thismia, is described and illustrated. It was found at a locality in the upland areas of Genting Highlands, Pahang, Malaysia. This new species is morphologically similar to members of Thismia sect. Geomitra, but differs in several characteristics, including the colour of the floral tube, the inner surface of the floral tube with longitudinal ribs and absent transverse bars, a stamen apex with a central lobe (prolongation of the rib) and two lateral lobes (the tips of each are recurved) and a black-purplish stigma. Thismia limkokthayi is provisionally classified as Critically Endangered according to the IUCN Red List Categories and Criteria.

Silva, Diego Ferreira Da, Honório, Mayk, Silva, Chirley Gonçalves, Teixeira-Silva, Márcia A., Silveira, Marcos, Braga, João Marcelo Alvarenga (2023): Two new species of Thismia (Thismiaceae) from the Brazilian Amazon Forest. Phytotaxa 587 (3): 269-282, DOI: 10.11646/phytotaxa.587.3.5, URL: http://dx.doi.org/10.11646/phytotaxa.587.3.5

A new mycoheterotrophic species, Thismia kenyirensis Siti-Munirah & Dome from Peninsular Malaysia, is described and illustrated. Thismia kenyirensis differs from other previously described species in the following characteristics: the flower tube is completely orange, with alternating darker and paler-coloured longitudinal lines on the outer and inner surfaces, the outer tepals are ovate (petaloid), the inner tepals are narrowly lanceolate, each ending with a long appendage. According to the IUCN Red List categories and criteria, T. kenyirensis is provisionally classified as Least Concern.

Knowledge on the mycoheterotrophic genus Thismia (Thismiaceae) in the neotropics is scarce, where the majority of species are known from Brazil, with 13 currently accepted species, of which seven are endemics. All the 15 known species of the genus in the Americas, except T. americana, inhabit forests below 1300 m a.s.l. Two species of Thismia are known from Colombia, T. panamensis from the Chocó biogeographical region and T. glaziovii from the Amazonian region. Here we describe a third Colombian species, T. andicola sp. nov. distinguished by having outer surface of the floral tube light blue and densely punctate with sky-blue metallic dots, inner tepals 4.6–5 mm long and stigma obovoid, covered adaxially by regularly distributed simple uniseriate multicellular trichomes. It is collected in the buffer zone of the Tamá National Park, Norte de Santander and is the first species of Thismia recorded from the Andes, and the first American species found above 2000 m a.s.l. We provide a description, drawings, photographs, distribution map, and the provisional conservation status of the new species. A key to species of Thismia sect. Ophiomeris species is also included.

A new species of Thismia (Thismiaceae) from the Brazilian Atlantic Forest is described and illustrated. Thismia cordata belongs to T. subg. Ophiomeris sect. Ophiomeris, and is mainly characterized by its flowers zygomorphic with gibbous perianth tube which is densely pilose on the inner surface, annulus surrounded by a prominent star-shaped ornamentation of 6-lobes with apex acute, densely pilose, outer perianth lobes ovate with base cordate, stamens with connective falcate, ovary glabrous, and stigma sharply trilobed, densely pilose. Detailed description, illustrations, notes on distribution, and preliminary conservation assessment are provided below.

In the present study, we describe and illustrate Thismia mantiqueirensis, a new mycoheterotrophic species belonging to the subgenus Ophiomeris, section Ophiomeris, from the Altomontane Dense Ombrophilous Forest in Mantiqueira mountains, southeast Brazil. We provide the description, taxonomic, ecological, and conservation comments, as well as images and illustrations of the new species.

Thismia petasiformis is described and illustrated as a new achlorophyllous mycoheterotrophic species discovered in the Brazilian Amazon Forest. The species belongs to Thismia subg. Ophiomeris sect. Pyramidalis by the presence of horizontal cylindrical roots, terete stem with scattered leaves, pyramidal stigma, and stamens flattened with connective not dilated, interstaminal lobes absent and ovary with parietal placentation from the base to the top of the ovary. Thismia petasiformis differs from T. fungiformis by the perianth tube apparently trigonous with slightly curved sides, annulus inconspicuous, and inner perianth lobes forming a single hat-shaped mitre. We present a taxonomic treatment for T. petasiformis, with a detailed description, illustrations and a preliminary assessment of its conservation status following IUCN categories and criteria.

A new species of Burmannia (Burmanniaceae), endemic to the southern Western Ghats of Kerala, India is described as Burmannia munnarensis and illustrations are provided. The new species is morphologically most similar to B. indica but can be easily distinguished by its narrow flower wings, involute margin of the perianth lobes, shorter perianth tube and shape of inflorescence. Burmannia indica, known only from the type locality Peermade in Idukki district, Kerala, is rediscovered after a lapse of 110 years on another locality, Meenuliyanpara in the same district. Key to the Indian species of Burmannia is included and status of both taxa is provisionally assessed as per IUCN Red List Categories and Criteria.

This report describes Thismia belumensis Siti-Munirah & Suhaimi-Miloko, a novel species of achlorophyllous herb discovered in the Royal Belum State Park, Peninsular Malaysia. This new species is unlike any previously described species of Thismia. In particular, T. belumensis possesses a unique annulus, which has been expanded and modified into a cucullate (hood-like) structure. This structure covers the apical floral tube and has an opening on one side facing a thickened part of the annulus, and the off-centre floral aperture confers a zygomorphic symmetry to the flower, indicating T. belumensis is more similar to Thismia labiata J.J.Sm. This morphological detail makes this new species distinct from all other described species of Thismia. In this report, we provide descriptions, illustrations, colour plates, and the provisional conservation status of Thismia belumensis.

Mycoheterotrophic plants (MHPs) growing on arbuscular mycorrhizal fungi (AMF) usually maintain specialized mycorrhizal associations. The level of specificity varies between MHPs, although it remains largely unknown whether interactions with mycorrhizal fungi differ by plant lineage, species, and/or by population. Here, we investigate the mycorrhizal interactions among Burmannia species (Burmanniaceae) with different trophic modes using high-throughput DNA sequencing. We characterized the inter- and intraspecific dynamics of the fungal communities by assessing the composition and diversity of fungi among sites. We found that fully mycoheterotrophic species are more specialized in their fungal associations than chlorophyllous species, and that this specialization possibly results from the gradual loss of some fungal groups. In particular, although many fungal species were shared by different Burmannia species, fully MHP species typically host species-specific fungal assemblages, suggesting that they have a preference for the selected fungi. Although no apparent cophylogenetic relationship was detected between fungi and plants, we observe that evolutionarily closely related plants tend to have a greater proportion of shared or closely related fungal partners. Our findings suggest a host preference and specialization toward fungal assemblages in Burmannia, improving understanding of interactions between MHPs and fungi.

An updated checklist of the family Burmanniaceae in Cambodia, Laos and Vietnam is provided. The checklist comprises a single genus, Burmannia, and 15 species, of which one is fully autotrophic, six species are partially mycoheterotrophic, and eight species are fully mycoheterotrophic (non-photosynthetic). Burmannia itoana earlier known only from Japan and China is reported from Vietnam for the first time, based on our collections of this species from northern and southern parts of the country. The newly recorded species, as well as a selection of several other Vietnamese species of Burmannia, are illustrated with analytical photographs of floral structure. A key for identification of Burmannia in the countries of Eastern Indochina is presented.

Thismia latiffiana Siti-Munirah & Dome, a new species from Terengganu, Peninsular Malaysia, is described and illustrated. The new species differs from all other species of Thismia, described so far, in having golden trichomes that are present on the outer surface of its floral tube and mitre, as well as pyramidal protuberances on the inner surface of the floral tube. Additionally, it is remarkable in its supraconnective apically bearing two long trichomes. Thismia latiffiana is assigned a preliminary conservation status as Critically Endangered (CR) according to IUCN Criteria.

Due to morphological reduction and absence of amplifiable plastid genes, the identification of photosynthetic relatives of heterotrophic plants is problematic. Although nuclear and mitochondrial gene sequences may offer a welcome alternative source of phylogenetic markers, the presence of rate heterogeneity in these genes may introduce bias/systematic error in phylogenetic analyses. We examine the phylogenetic position of Thismiaceae based on nuclear 18S rDNA and mitochondrial atpA DNA sequence data, as well as using parsimony, likelihood and Bayesian inference methods. Significant differences in evolutionary rates of these genes between closely related taxa lead to conflicting results: while parsimony analyses of 18S rDNA and combined data strongly support the monophyly of Thismiaceae, Bayesian inference, with and without a relaxed molecular clock, as well as the Swofford-Olsen-Waddell-Hillis (SOWH) test confidently reject this hypothesis. We show that rate heterogeneity in our data leads to long-branch attraction artifacts in parsimony analysis. However, using model-based inference methods the question of whether Thismiaceae are monophyletic remains elusive. On the one hand maximum likelihood nonparametric bootstrapping and parametric hypothesis tests fail to support a paraphyletic Thismiaceae, on the other hand Bayesian inference methods (both without and with a relaxed clock) significantly reject a monophyletic Thismiaceae. These results show that an adequate sampling, the use of rate homogeneous data, and the application of different inference methods are important factors for developing phylogenetic hypotheses of myco-heterotrophic plants. (C) The Willi Hennig Society 2009. ispartof: Cladistics vol:25 issue:1 pages:64-77 ispartof: location:United States status: published

Plants producing dust seeds often meet their carbon demands by exploiting fungi at the seedling stage. This germination strategy (i.e. mycoheterotrophic germination) has been investigated among orchidaceous and ericaceous plants exploiting Ascomycota or Basidiomycota. Although several other angiosperm lineages have evolved fully mycoheterotrophic relationships with Glomeromycota, the fungal identities involved in mycoheterotrophic germination remain largely unknown. Here, we conducted in situ seed baiting and high-throughput DNA barcoding to identify mycobionts associated with seedlings of Burmannia championii (Burmanniaceae: Dioscoreales) and Sciaphila megastyla (Triuridaceae: Pandanales), which have independently evolved full mycoheterotrophy. Subsequently, we revealed that both seedlings and adults in B. championii and S. megastyla predominantly associate with Glomeraceae. However, mycorrhizal communities are somewhat distinct between seedling and adult stages, particularly in S. megastyla. Notably, the dissimilarity of mycorrhizal communities between S. megastyla adult samples and S. megastyla seedling samples is significantly higher than that between B. championi adult samples and S. megastyla adult samples, based on some indices. This pattern is possibly due to both mycorrhizal shifts during ontogenetic development and convergent recruitment of cheating-susceptible fungi. The extensive fungal overlap in two unrelated mycoheterotrophic plants indicates that both species convergently exploit specific AM fungal phylotypes.

A new species of Thismia (Thismiaceae), T. jianfenglingensis, is described and illustrated from Hainan Island, China. The new species is similar to T. hongkongensis, displaying a urecolate perianth tube, a loose dome with six perianth lobes, six stamens, and three stigmas. T. jianfenglingensis differs from T. hongkongensis in the color and morphology of perianth tube, the position of outer perianth lobes, the morphology and appendage of connective apex, the morphology of stigmas. The new species is only reported to occur on Hainan Island, China and it is proposed to be Vulnerable (VU) according to the IUCN criteria for the conservation status of plant species due to having a population with a very restricted area of occupancy or number of locations such that it is prone to become critically endangered or even extinct in a very short time period.

During a recent survey, Oxygyne specimens were discovered in three lowland evergreen forests on Okinawa Island, Japan. After morphological investigation, we identified the specimens as O. shinzatoi. Intriguingly, the colour of the specimens from one of the localities was significantly different from that of specimens collected from both the type and two of the new localities. Furthermore, morphological analysis also revealed clear differences between specimens collected from the type locality, including the type specimen, and previous descriptions of O. shinzatoi. Therefore, an amended description of O. shinzatoi is provided, based on the type and newly collected specimens. Phylogenetic relationships of Oxygyne from Japan and western Central Africa are also discussed, with consideration of the characteristics of newly discovered colour variation.

Gymnosiphon tenellus (Bentham) Urban is recorded for the first time in the state of Paraná and in southern Brazil. Until now it has only been known to occur in Central America, the Amazonian Rainforest, and in the Atlantic Rainforest of the state of Rio de Janeiro in southeastern Brazil. An updated description is provided, along with original, detailed pictures of the species.

Two new species of the mycoheterotrophic genus Thismia Griff. (Thismiaceae), Thismiadomei Siti-Munirah and T.terengganuensis Siti-Munirah from Peninsular Malaysia, are described and illustrated. Thismiadomei, characterized by its perianth lobes that are upright and curve inward, but are imperfectly connate, falls within sectionOdoardoa. Thismiaterengganuensis is characterized by its mitre with three appendages on its apex, so falls within sectionGeomitra. Both new species are unique and totally different from other described species, T.domei by the trichomes on its outer perianth tube surface and T.terengganuensis by its mitre with slender appendages. Thismiajavanica J.J.Sm, also from Terengganu, is a new record for Peninsular Malaysia.

We describe an extraordinary new species in the genus Thismia from the Terengganu State of Malaysia in the Malay Peninsula. The new species, which we name Thismia sitimeriamiae, is distinct from all other Thismia species known to science, most notably in its unique mitre configuration formed by the inner tepals and its floral surface morphology characterised by conspicuous orange trichomes. We discuss our findings in the context of underestimated species diversity in the genus Thismia and implications for their conservation. We recommend assigning T. sitimeriamiae the conservation status as Critically Endangered (CR) according to IUCN criteria.

The Dioscoreaceae is a monocotyledonous family belonging to the order Dioscoreales. It includes two other families, the Burmanniaceae and the Nartheciaceae. Dioscoreaceae is the largest family of this order comprising 650–700 extant species included in four genera, which are widely distributed throughout warm temperate, subtropical and tropical regions. It is a pantropical family with a disjunct distribution. A new fossil species, Dioscorea eocenicus Mehrotra and Shukla, is described from the early Eocene sediments of Bikaner district (northwestern India). The campylodromous venation (having nine primary veins), disposition and course of tertiary veins, and other attributes of the fossil show its affinity with the modern genus Dioscorea of the family Dioscoreaceae. The origin, evolution, and diversification of the family have always been a matter of concern as different views and theories exist. This is the first fossil record of the family Dioscoreaceae from Asia. To date, fossils belonging to the family Dioscoreaceae have been retrieved only from Europe, Africa, and America. The present fossil from the Indian subcontinent, along with earlier recorded fossils of the family Dioscoreaceae provides new opportunities to trace the presence of Dioscorea (yams) in Gondwana since the Cretaceous. The presence of humid tropical forest in the region during early Eocene time has been interpreted based on this and other described fossils from the Gurha lignite mine.

A new holomycoheterotrophic member of Burmanniaceae, Gymnosiphon syceorosensis, is described from Mt. Hamiguitan located on the island of Mindanao, Philippines. This species differs from the recently named G. philippinensis from Cebu in a number of quantitative and qualitative characters. Phenetic (neighbor-joining) and phylogenetic (maximum parsimony) analyses of characters from Asian and Australian Gymnosiphon species were conducted and diagnostic taxonomic features were discussed. This new species appears to be most closely related to G. affinis J.J. Sm. from New Guinea but differs in a number of floral features including inner perianth lobe shape, stamen position in floral tube, and anther connective shape.

A new species of the mycoheterotrophic genus Thismia Griff. (Thismiaceae), Thismiasumatrana Suetsugu & Tsukaya, from West Sumatra, Indonesia, is described, based on a rehydrated herbarium specimen from National Museum of Nature and Science, Japan. Thismiasumatrana is closely related to T.clavigera (Becc.) F.Muell. but is distinguished by a much larger flower.

Burmanniaceae is one major group within the monocot order Dioscoreales that has not had its plastome sequenced. Members of Burmanniaceae are mostly achlorophyllous, although the genus Burmannia also includes autotrophs. Here, we report sequencing and analysis of the first Burmanniaceae plastid genome from Burmannia disticha L.. This plastome is 157,480 bp and was assembled as a circular sequence with the typical quadripartite structure of plant plastid genomes. This plastome has a regular number of potentially functional genes with a total of 111, including 78 protein coding genes, 4 ribosomal RNA (rRNA) genes, and 29 tRNA genes. The ratio of the total length of genic:intergenic DNA is 1.58:1, and the mean length of intergenic regions is 398 bp, the longest being 1918 bp. The overall GC content of the B. disticha plastome is 34.90%, and the IR regions in B. disticha are more GC rich (39.50%) than the LSC (32.30%) and SSC (28.80%) regions. Phylogenetic analysis of protein-coding sequences from plastomes of related species in the order Dioscoreales support a clade comprising Burmanniaceae and Dioscoreaceae. This phylogenetic placement is congruent with previous findings based on nuclear and mitochondrial evidence. Keywords: Burmannia disticha, Burmanniaceae, Plastome, Phylogenetic analysis

Premise of the study Phylogenomic studies employing large numbers of genes, including those based on plastid genomes (plastomes), are becoming common. Nonphotosynthetic plants such as mycoheterotrophs (which rely on root-associated fungi for essential nutrients, including carbon) tend to have highly elevated rates of plastome evolution, substantial genome reduction, or both. Mycoheterotroph plastomes therefore provide excellent test cases for investigating how extreme conditions impact phylogenomic inference. Methods We used parsimony and likelihood analysis of protein-coding gene sets from published and newly completed plastomes to infer the phylogenetic placement of taxa from the 10 angiosperm families in which mycoheterotrophy evolved. Key results Despite multiple very long branches that reflect elevated substitution rates, and frequently patchy gene recovery due to genome reduction, inferred phylogenetic placements of most mycoheterotrophic lineages in DNA-based likelihood analyses are both well supported and congruent with other studies. Amino-acid-based likelihood placements are broadly consistent with DNA-based inferences, but extremely rate-elevated taxa can have unexpected placements-albeit with weak support. In contrast, parsimony analysis is strongly misled by long-branch attraction among many distantly related mycoheterotrophic monocots. Conclusions Mycoheterotrophic plastomes provide challenging cases for phylogenomic inference, as substitutional rates can be elevated and genome reduction can lead to sparse gene recovery. Nonetheless, diverse likelihood frameworks provide generally well-supported and mutually concordant phylogenetic placements of mycoheterotrophs, consistent with recent phylogenetic studies and angiosperm-wide classifications. Previous predictions of parallel photosynthesis loss within families are supported for Burmanniaceae, Ericaceae, Gentianaceae, and Orchidaceae. Burmanniaceae and Thismiaceae should not be combined as a single family in Dioscoreales.

The mycoheterotrophic genus Gymnosiphon Blume is recorded for Australia for the first time after the recent discovery of plants at Mossman Gorge, Queensland. On the basis of examination of living plants in the field as well as materials preserved in spirit, the Mossman Gorge Gymnosiphon taxon is a novelty closely related to Gymnosiphon affinis J.J.Sm., which is known only from New Guinea. The new species is here described as Gymnosiphon queenslandicus B.Gray & Y.W.Low based on floral characteristics important for species distinction in the genus.

The Burmanniaceae contain several lineages of achlorophyllous mycoheterotrophic plants that associate with arbuscular mycorrhizal fungi (AMF). Here we investigate the isotopic profile of a green and potentially mycoheterotrophic plant in situ, Burmannia coelestis, and associated reference plants. We generated δ 13C and δ 15N stable isotope profiles for five populations of B. coelestis. Burmannia coelestis was significantly enriched in 13C relative to surrounding C3 reference plants and significantly depleted in 13C relative to C4 reference plants. No significant differences were detected in 15N enrichment between B. coelestis and reference plants. The isotopic profiles measured are suggestive of partial mycoheterotrophy in B. coelestis. Within the genus Burmannia transitions to full mycoheterotrophy have occurred numerous times, suggesting that some green Burmannia species are likely to be partially mycoheterotrophic but in many conditions this mode of nutrition may only be detectable using natural abundance stable isotopic methods, such as when associated with C4 mycorrhizal plants.

Gymnosiphon philippinensis is described as a new species of Burmanniaceae from forest over limestone in southern Cebu (Philippines). Among Malesian Gymnosiphon, it is most similar to G. papuanus and G. pauciflorus in having flowers with stamens that are attached in the middle of the floral tube and having outer tepals with entire margins, but these tepals are longer in absolute and relative lengths than those of the aforementioned species. Gymnosiphon philippinensis is the first species of Gymnosiphon reported from the Philippines.

Premise of research. One hundred and one years ago, Thismia americana was discovered in a prairie near Chicago in the United States. This tiny mycoheterotrophic plant was observed at the type locality for a few years but is now considered to be extinct. The occurrence of the mainly tropical genus Thismia in temperate North America remains a mystery, particularly because T. americana’s putative most closely related species occurs in Australia and New Zealand. Here we evaluate the affinities of T. americana using morphological data and the relationships of the two other species in Thismia subgen. Thismia sect. Rodwaya with molecular data.Methodology. A 21-character morphological data set of 50 Thismia species was analyzed with parsimony and Bayesian phylogenetic analyses. A data set of eight species of Thismia and allied taxa containing sequence data of the nuclear 18S and mitochondrial atp1 regions was analyzed with maximum likelihood and Bayesian phylogeny inference methods, including a Bayesian relaxed m...

Summary. Two new species of Afrothismia are described within the framework of an intended revision of the genus in Cameroon, A. fungiformis from the submontane forest of Mt Kupe and A. pusilla from Mt Kala. The new species are illustrated and the conservation status for both is assessed as Critically Endangered.

Nonphotosynthetic mycorrhizal plants, so-called mycoheterotrophic plants, have long attracted the curiosity of botanists and mycologists. Recent advances in molecular methods based on fungal-specific PCR amplification have dramatically enhanced the identification of their host mycorrhizal fungi. However, studies investigating the fungal hosts of arbuscular mycorrhizae-forming mycoheterotrophs are still limited in Asia, which is known as one of the diversity hot spots of mycoheterotrophs that parasitize arbuscular mycorrhizae (AM). Therefore, we aimed to reveal the mycorrhizal associations of two Asian, fully mycoheterotrophic Burmannia species by molecular identification. Sequences of the small subunit ribosomal DNA showed that both Burmannia species are associated with several distinct lineages of Glomus group Ab. Because Glomus group Ab fungi have been confirmed as fungal hosts of various mycoheterotrophic plants in Africa and South America, we suggest they are widely exploited by AM-forming mycoheterotrophs globally.

Thismia filiformis is described and illustrated as a new species from Khao Yai National Park, Thailand. The conservation status and affinities of the new species are discussed.

A new species of Thismiaceae, Thismia betung-kerihunensis Tsukaya et H. Okada, found during a botanical survey of Betung-Kerihun National Park, West Kalimantan, Borneo, Indonesia, is described and illustrated. This species closely resembles Thismia clavigera (Becc.) F. Muell, which is distributed in Borneo, Sumatra, Langkawi, and Thailand; however, it differs in flower shape, size, and color, having conspicuous hood-like appendages at the tip of the brilliant blue-green colored mitre formed by the three inner tepals. Moreover, it differs in the shape of the anther connectives that lack acutely elongated apices and has rectangular glands. The smaller stature of the species also distinguishes it from T. clavigera.

A new species of Burmannia (Burmanniaceae), Burmannia bengkuluensis Tsukaya et Daernadi, discovered in a swamp adjacent to Bengkulu Airport, Sumatra, Indonesia, is described. It has poorly developed photosynthetic leaves and resembles B. ledermannii Jonker, described from a specimen collected in Palau, in having poorly developed leaves, narrowly 3-winged erect flowers, and in particular, funnel-shaped anthers, but differs in having dark purple flowers, longer outer perianth lobes, well-developed, fan-shaped inner perianth lobes, and a thick and short style. Sequence data on genomic DNA regions covering ITS1 and ITS2 are also provided.

Burmannia championii Thwaites, is a small saphrophytic herb of family Burmanniaceae. This has been discovered from two locations in the central Western Ghats of Karnataka in southern India. Present report of Burmannia championii Thwaites forms a new addition to the flora of Karnataka.

Thismia Griffith (1844: 221), Thismiaceae J. Agardh or Burmanniaceae sensu APG VI (2016), is one of the most species-rich mycoheterotrophic genera, consisting of ca. 80 species (Jonker 1948, Merckx et al. 2013). Considering that most of these species were collected only once (Jonker 1948) and that many new species have recently been discovered in various Asian countries (e.g. Suetsugu et al. 2017, 2018), many more undescribed species are likely in these regions.

A new species of Thismia (Thismiaceae), T. kinabaluensis, is described from Mt. Kinabalu, Sabah, Borneo. Thismia kinabaluensis is clearly placed in section Thismia subsect. Odoardoa, in having its creeping vermiform roots and free and equal perianth lobes, and it is distinguished from the other members of this subsection by three anther appendages (one filiform appendage between two club shaped ones) and a pale-blue perianth tube with transverse bars inside. A key to the Malaysian Thismia is provided for easy identification of these mycoheterotrophic plants.

Five species of achlorophyllous heteromycotrophs, better known as saprophytes, are here reported from Guinea for the first time, raising the national total to six. They include a new species, Gymnosiphon samoritoureanus Cheek, which is described and illustrated, and assessed as Vulnerable using IUCN (2001).

Gymnosiphon marieae Cheek sp. nov. from Madagascar is described and its conservation status assessed. The discovery of tepal-mediated stigmatic extension in Gymnosiphon is reported.

The complete ontogeny of the mycoheterotrophic Afrothismia hydra (Burmanniaceae) from seed to seed dispersal is presented. The oblong–ovoidal seeds are up to 0.7 mm long. They germinate with root tissue only, disrupting the seed coat and developing a primary ovoid root tubercle. At the proximal end of the tubercle, a second tubercle arises and further root initials indicate the sequential growth of more root tubercles with filiform extensions resulting in a small root aggregate. The seed coat often remains attached to this structure. When the root aggregate enlarges, a central axis to which all roots are connected becomes visible. This axis has a growth pole where new root tubercles arise. The same growth pole will later develop into a stem with scale leaves finally terminating in a flower. Flowers develop sympodially when the mature plant is only several centimetres long. After anthesis, the corolla tube disintegrates, leaving a pyxidium which opens by means of a peculiar elongating placenta, here called ‘placentophore’. The placentophore elevates the placenta with attached seeds above the flowering level and is interpreted as an adaptation to ombrohydrochory. The reduction of hypocotyl, cotyledon and primary shoot is discussed with regard to the classical germination concepts of monocotyledons and with mycoheterotrophic dicotyledons. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 157, 31–36.

We amplified and sequenced partial 18S rDNA of fungi in the roots of 11 African myco-heterotrophic plants out of four angiosperm families (Burmanniaceae, Thismiaceae, Triuridaceae, and Gentianaceae). The sequences were cladistically analyzed with published sequences of arbuscular mycorrhizal fungi. We show that all investigated African myco-heterotrophic plants are associated with arbuscular mycorrhizal fungi within a clade of Glomus (Glomus-group A). We reveal a fine-level mycorrhizal specificity for a particular set of arbuscular mycorrhizal fungi within Glomus-group A by Afrothismia hydra (Thismiaceae). Furthermore, we show that the roots of two myco-heterotrophic plant individuals, besides being colonized by representatives of Glomus-group A, also contain DNA of Acaulospora sp. Consequently, Acaulospora is interpreted as a facultative mycorrhizal associate.

Sainge, M. N., Franke, T. & Agerer, R.: A new species of Afrothismia (Burmanniaceae, tribe Thismieae) from Korup National Park, Cameroon. – Willdenowia 35: 287-291. – ISSN 0511-9618; © 2005 BGBM Berlin-Dahlem. doi:10.3372/wi.35.35209 (available via http://dx.doi.org/) Afrothismia korupensis, a new species of this genus of achlorophyllous, myco-heterotrophic herbs is described from evergreen Guineo-Congolean rain forest in the Korup National Park, Cameroon, and illustrated. It differs from all other species of the genus in the internal structure of its perianth tube with six radially arranged cuneate partitions at the base, the absence of an internal flange and the laterally winged staminal filaments, each with a conical projection.

Afrothismia foertheriana, a new species of Burmanniaceae (tribe: Thismieae) from the peripheral zone of the Onge Forest Reserve in Cameroon’s Southwest Province is described and illustrated. The papillose, multicellular floral trichomes, the tepal’s erose margins, the small, zygomorphic perianth mouth and the dull purplish brown coloration give A. foertheriana a distinctive appearance within the genus. The species is here assessed as being critically endangered.

A new species of Afrothismia, A. gesnerioides H. Maas is described and illustrated. A key to the genus Afrothismia is included.

Afrothismia hydra, a new species of Burmanniaceae (tribe Thismieae) from South west Cameroon is decribed, illustrated and compared with related taxa.

Corsiaceae is a small family of mycoheterotrophic herbs composed of the genera Arachnitis, Corsia, and Corsiopsis. Due to a lack of DNA sequence data, previous molecular‐based phylogenetic studies have not addressed adequately the position or circumscription of the family. Because mycoheterotrophy results in extreme vegetative reduction that may contribute to homoplasy in the form of character convergence, morphological‐based studies that have addressed these issues may be misleading. Traditionally, Corsiaceae have been grouped with Burmanniaceae and Thismiaceae. However, other than mycoheterotrophy, there are few characters that support this relationship. Additionally, the monophyly of Arachnitis, Corsia, and Corsiopsis has been questioned. The present phylogenetic study, inferred from large‐subunit (26S) ribosome DNA sequences, suggests that Corsiaceae are polyphyletic. Specifically, Corsia clusters with the order Liliales and Arachnitis appears as sister to Thismia (Thismiaceae) in a larger cl...

Thismia neptunis, as many of its congeners, is a poorly understood species that has only been known from the type collection and its limited original description. In January 2017 it was rediscovered in the type area in the Gunung Matang massif, western Sarawak, Borneo, Malaysia. The paper provides the amended description and drawings of the species, very first available photographs and short notes on taxonomy and historical context of Beccari’s work on Thismia.

The genus Thismia Griffith (1844: 221) of the tribe Thismieae, Burmanniaceae sensu APG IV (2016) or Thismiaceae of other authors, represents one of the most species-rich mycoheterotrophic genera and consists of more than 60 species (Jonker 1948, Merckx 2008). Considering that the majority of these species were collected only once (Jonker 1948), and that many new species have recently been discovered, especially from various Southeast Asian countries (e.g., Tsukaya & Okada 2012, Dančák et al. 2013, Nuraliev et al. 2014, 2015, Truong et al. 2014, Chantanaorrapint & Sridith 2015, Li & Bi 2013, Hroneš et al. 2015, Tsukaya et al. 2017, Suetsugu et al. 2017), many more undescribed species are probably still hidden in the tropical rain forests of Southeast Asia.

A new species, Thismia hongkongensis S.S.Mar & R.M.K.Saunders, is described from Hong Kong. It is most closely related to Thismia brunonis Griff. from Myanmar, but differs in the number of flowers per inflorescence, the colour of the perianth tube, the length of the filaments, and the shape of the stigma lobes. We also provide inferences on the pollination ecology and seed dispersal of the new species, based on field observations and interpretations of morphology. The flowers are visited by fungus gnats (Myctophilidae or Sciaridae) and scuttle flies (Phoridae), which are likely to enter the perianth tube via the annulus below the filiform tepal appendages, and exit via small apertures between the filaments of the pendent stamens. The flowers are inferred to be protandrous, and flies visiting late-anthetic (pistillate-phase) flowers are possibly trapped within the flower, increasing chances of pollen deposition on the receptive stigma. The seeds are likely to be dispersed by rain splash.

Analyses of morphological and molecular characters for Dioscoreales Hook, f. (Chase & al., 1995b; Caddick & al., 2000a; Caddick & al., 2002) have redefined the order, which now comprises three families, Burmanniaceae, Dioscoreaceae, and Nartheciaceae. Since recent analyses of morphological and molecular data sets (Caddick & al., 2002) have indicated well-supported relationships within Dioscoreaceae R. Br., a formal reclassification of the family is presented here. Dioscoreaceae now contain four distinct genera, Dioscorea, Stenomeris, Tacca (previously in Taccaceae), and Trichopus. The Malagasy endemic Avetra sempervirens is close sister to Trichopus zeylanicus, and is here reclassified as a second species of this genus. The dioecious Dioscoreaceae genera, Borderea, Epipetrum, Nanarepenta, Rajania, Tamus, and Testudinaria, are nested within Dioscorea in phylogenetic analyses (Caddick & al., 2002), and are therefore sunk into it.